Comparison of enoxaparin and warfarin for the prevention of venous thromboembolic disease after total hip arthroplasty - Evaluation during hospitalization and three months after discharge

Background: Venous thromboermbolic disease in the form of deep venous throm bosis and pulmonary embolism is a major risk after a total hip arthroplasty -Enoxaparin, a low- molecular-weight heparin, has been shown to reduce the prevalence of deep venous thrombosis after total hip arthroplasty, Warfarin , an orally administered anticoagulant, has been used historically to reduc e the risk of deep venous thrombosis after total hip arthroplasty. Methods: We compared enoxaparin and adjusted-dose warfarin with respect to their safety and their efficacy in the prevention of clinically important v enous thromboembolic disease, defined as distal or proximal deep venous thr ombosis or pulmonary embolism. or both, during hospitalization after total hip arthroplasty, We also evaluated the prevalence of complications and mor tality from venous thromboembolic disease within three months after dischar ge. Results: Three thousand and eleven patients at 156 centers were randomly as signed to prophylactic treatment with injection of enoxaparin or oral admin istration of adjusted-dose Warfarin during hospitalization. During the stud y, fifty-five (3.6 percent) of the 1516 patients who were managed with enox aparin and fifty-six (3.7 percent) of the 1495 patients who were managed wi th warfarin had venous thromboembolic disease. Twenty-one patients (0.7 per cent), which included four (0.3 percent) of those managed with enoxaparin a nd seventeen (1.1 percent) of those managed with Warfarin (p = 0.0083), had ,venous thromboembolic disease during hospitalization. After discharge from the hospital, venous thromboembolic disease developed in ninety patients ( 3.0 percent): fifty-one (3.4 percent) of those managed with enoxaparin and thirty-nine (2.6 percent) of those managed with warfarin. One patient who h ad been managed with enoxaparin died because of a pulmonary embolism which was confirmed at autopsy. Three additional patients (one who had been manag ed with enoxaparin and two who had been managed with warfarin) died, and th e deaths were attributed to venous thromboembolic disease; however, no auto psies were performed. Twenty-six patients (0.9 percent) (eighteen managed w ith enoxaparin and eight managed with warfarin) had clinically important bl eeding. Conclusions: Inpatient programs providing treatment with either enoxaparin (thirty milligrams every twelve hours) or adjusted-dose warfarin for a mean of 7.3 days afforded protection against venous thromboembolic disease, wit h overall rates of morbidity and mortality of 3.7 and 0.6 percent, respecti vely, and a very lon rate of major bleeding complications (0.9 percent) for three months after total hip arthroplasty: During hospitalization, the pat ients managed with enoxaparin had a lon er rate of venous thromboembolic di sease than those managed with adjusted-dose warfarin (p = 0.0083). This ben efit was lost after the medication was discontinued, with no difference in the prevalences of venous thromboembolic disease between the two groups at three months after discharge from the hospital.